The present disclosure relates to a zoom lens and an imaging apparatus. More particularly, the disclosure relates to a technique of a zoom lens which is miniaturized and increased in variable magnification and which is suitable for an image capturing optical system of a digital I/O apparatus such as a digital still camera or a digital video camera, and an imaging apparatus including the same.
In recent years, an imaging apparatus such as a digital still camera using a solid-state imaging element is becoming widely use. Along with such popularization of the digital still camera, the further increased image quality is required. In the digital still camera or the like having a large number of pixels, an image capturing lens superior in imaging performance, especially, a zoom lens is required. In addition, beside this, a request for miniaturization, an increased field angle, and an increased variable magnification is also recently high. Thus, a high-performance and compact zoom lens is required.
There are many kinds of zoom lenses for use in the digital still camera. A three-group zoom optical system is known as a lens type suitable for the miniaturization and the increased field angle. In this case, in the three-group zoom optical system, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having the positive refractive power are disposed in order from an object side to an image side. Such a three-group zoom optical system, for example, is described in Japanese Patent Laid-Open Nos. 2007-102182, 2007-14059, 2008-241794, 2008-292911, 2009-20337, and 2009-251433 (hereinafter referred to as Patent Documents 1 to 6).
In each of the zoom lenses described in Patent Documents 1 to 6, there is proposed a compact zoom lens in which the first lens group is composed of two sheets of lenses.